A Study on Rupture Resistance of Groundnut (cv. SAMNUT 22) Kernel

Abstract

This study was done to assess the influence of compression loading rate and kernel size on the rupture resistance of groundnut (cv. SAMNUT 22) kernel. These groundnut kernel mechanical parameters (rupture force, deformation at rupture, rupture power, firmness and toughness) were evaluated under three loading rates (15 mm min-1, 20 mm min-1 and 25 mm min-1), and three size categories (small, medium and large). The groundnut kernels were harvested at peak maturity stage, and tested in accordance to ASTM International standards. Results obtained from the tests showed that the rupture resistance of SAMNUT 22 kernel was highly dependent on its size and the loading rate. Generally, as the loading rate increases, the mechanical parameters values declined significantly (p ≤ 0.05). Rupture force, deformation at rupture point, rupture power and the firmness increased as the kernel size increases; but in contrast, the kernel toughness decreases as its size increased. An average force of 57.96 N ruptured the large kernel, while a lower force of 27.35 N ruptured the small kernel. Moreover, the large kernel recorded the highest firmness (59.03 N mm-1), when compared to the medium (51.69 N mm-1) and small (44.98 N mm-1) size kernel. In terms of rupture power, the small kernel power ranged from 0.1002 W (15 mm min-1) to 0.084 W (25 mm min-1); medium size kernel ranged from 0.115 W (15 mm min-1) to 0.074 W (25 mm min- 1); while the large size kernel ranged from 0.135 W (15 mm min-1) to 0.104 W (25 mm min-1). These results portrayed importance of sorting of the groundnut kernels before processing unit operation, as it will help to conserve power and energy during the processing operation.